Coated paper.



'1' an snares PATENT caries.

JAMES MILN, F TORONTO, ONTARIO, CANADA.

COATED PAPER.

No Drawing.

To all whom it may concern:

Be it known that I, JAmns MILN, of the city of Toronto, in the county of York and Province of Ontario, Dominion of Canada,

have invented certain new and useful Improvements in Coated Paper; and I hereby declare that the following is a full, clear, and exact description of the same.

The present invention relates to a coated paper which may be used in mechanical processes for the production of surfaces for printing illustrations swhen such surfaces are adapted to be attached to printing cylinders or platens or to the lower surfaces of printing blocks in such a manner that the pressure to be exerted upon the 'difl'erent parts of the sheet to be printed upon is regulated according to the light and shade of the picture, and the invention consists of applying to a paper surface a coating of etchable material, which, after the impression of the picture thereon with an etchproof color, is subjected to an etching process, whereby the high lights left uncovered or lightly covered by the color may be more or less deeply or completely etched by the action of the etching agent, and removed by washing or brushing.

In carrying out the invention, I employ an etchable mass consisting of a=mineral or metal body and an adhesive. Oxid of zinc,

commonly knownas zinc white, hydrated aluminum oxid, and calcium sulfate, commonly known as satin white, glue, and glycerin, are particularly suitable for this purpose, and may be combined in the proportion of forty parts of zinc white, fiftythree parts of satin white, five and seventenths parts of glue, and one and threetenths parts of glycerin, mixed or agitated to an appropriate consistency, at a temperature of about fifty degrees Fahrenheit, and

then smoothly or evenly applied to the paper by means of the felt roll and brushes of a coating machine, and dried on festoons, at a temperature of about one hundred degrees'Fahrenheit.

The paper, when it has been coated with this etchable mass, is calendered or pressed Specification of Letters Patent.

Patented May "3, 1918.

Application filed February 28, 1916. Serial No. 80,903.

between the calender rolls to produce a good made, first on one side and then on the other of the prepared paper sheet having on both sides the etchable coating.

1 The printed sheet of prepared paper is then subjected for a short time to the action of an' etching. agent to destroy the binding qualities of the adhesive in the etchable coating, where exposed to the action of such agent, and the coating, where the adhesive agent is so destroyed, is removed by washing or brushing, so that a relief is obtained corresponding to the picture.

It is thus possible to obtain by the use of a paper coated with an etchable material of this character, strong relief values accurately graduated in all details, and the height of the relief may be exactly regulated by the thickness of the coating and by the duration of the etching process.

Surfaces of the same tone are thus always of the same height, and when so produced, may be used as an overlay on the printing cylinder or platen, or as an underlay between the printing form and the support.

Any suitable etching agent, such as a solution of chlorid of lime, may be employed in the preparation of the etching bath to develop the relief.

Having thus fully described the nature of my invention, what I claim as new and desire to secure, by Letters Patent, is 1. In the hereindescribed article of manufacture, a sheet of paper having an etchable coating consisting of zinc white, satin white, and an adhesive.

2. In the hereindescnbed article of manumam, a shes-i; a5 paper having an afiachable parts of satin White, five and seven-tenths cmting consisting 0f zinc whim, swim White parts of" glue, ami one and thme-t mths parts 10 glue; and glycsfin of glycerin,

3a In file hereindescribed amide of mamn- Twontm February 22nd; 1916, 55 mature; a sheet of papa having an etchafble JAMES 'MILIL waking consisfiing of zinc White, satin white Signeci in the presmwe- 0fgiue and glywrin, combined in the pmpar= D, 8,, TQVELL; tiens 0f forty parts 0f zinc White, fifty-threa EDWAED St Bmmsmmn 

